Beem: Account.history() fails with float division by zero exception

Project Information

• Repository: https://github.com/holgern/beem
• Project Name: Beem
• Publisher: @holger80

A GitHub issue was created: https://github.com/holgern/beem/issues/34
A PR to fix the bug has been accepted by the PO: https://github.com/holgern/beem/pull/35

Expected behavior

Account.history(start, stop) with start and stop being datetime instances should return all account operations between the given timestamps

Actual behavior

Account.history(start, stop) sometimes fails with a ZeroDivisionError exception:

Traceback (most recent call last):
  File "history.py", line 15, in <module>
    for op in a.history(start, stop):
  File "/usr/local/lib/python3.6/site-packages/beem/account.py", line 1566, in history
    op_est = self.estimate_virtual_op_num(start, stop_diff=1)
  File "/usr/local/lib/python3.6/site-packages/beem/account.py", line 1333, in estimate_virtual_op_num
    op_diff = (blocktime - formatTimeString(trx["timestamp"])).total_seconds() / factor
ZeroDivisionError: float division by zero

How to reproduce

What actually fails is the op number lookup for a given timestamp via Account.estimate_virtual_op_num(). Here's a minimum example to reproduce the problem:

from beem.account import Account
from datetime import datetime, timedelta
from beem.utils import addTzInfo
a = Account("berniesanders")
start = addTzInfo(datetime(2017, 11, 16, 23, 23, 11))
print(a.estimate_virtual_op_num(start))

Output:

# python bug_divbyzero.py 
Traceback (most recent call last):
  File "bug_divbyzero.py", line 9, in <module>
    print(a.estimate_virtual_op_num(start))
  File "/usr/local/lib/python3.6/site-packages/beem/account.py", line 1333, in estimate_virtual_op_num
    op_diff = (blocktime - formatTimeString(trx["timestamp"])).total_seconds() / factor
ZeroDivisionError: float division by zero

The issue was caused by the fact that an account can have several ops in the same block. op_start_last[0][1]["timestamp"]) and trx["timestamp"] can be identical in this case. This makes factor = 0.

Another potential issue about the factor variable used without proper initialization was found close by: if diff_op == 0, the factor assignment was skipped and factor was used later on with the value from the previous iteration or from the initial assignment outside the while loop.

Environment

# beempy --version
beempy, version 0.19.40
# python --version
Python 3.6.5

Fix

A PR has been provided to fix both the division-by-zero exception as well as the possibly wrongly initialized factor variable:
https://github.com/holgern/beem/pull/35

The PR was accepted by the PO and the fix is contained in release beem-0.19.41

GitHub Account

https://github.com/crokkon